Components emitting electromagnetic radiation such as LEDs or OLEDs or lasers generate electromagnetic radiation having differing beam strengths and/or in different wavelength ranges, e.g., light of different colors, depending on their design. As a result, for different applications specific components emitting electromagnetic radiation may be chosen, the light intensity and/or the wavelength range of which, e.g., the color, is suitable for the respective field of application.
With increasing operating time, the components emitting electromagnetic radiation may, however, deteriorate, e.g., resulting in a decrease of efficiency and/or of light intensity and thus of the perceived brightness and/or resulting in a shift of the wavelength range of the generated electromagnetic radiation and thus of the perceived color.
Alternatively or additionally, the components emitting electromagnetic radiation may be temperature-sensitive so that, e.g., an increase in temperature may result in a decrease of efficiency and/or of illumination or, respectively, light intensity and thus of the perceived brightness, and/or may result in a shift of the wavelength range of the generated electromagnetic radiation and thus of the perceived color.
Those modifications of the electromagnetic radiation may, e.g., be compensated for by operating the corresponding components generating the electromagnetic radiation by an open control loop. Such an open control loop may, e.g., comprise a photo-sensor detecting the electro-magnetic radiation. Depending on the detected electromagnetic radiation, an energy supply, e.g., a voltage and/or current supply, to the corresponding component may be set such that the modifications caused by deterioration or temperature are completely or partially compensated for. Such open control loops, however, are relatively expensive and complex in manufacture.